Chapter 1: Group Consensus




  • What are the key chapter elements (take home messages) that I should test you on?




  • What new things are you curious about and/or did not fully understand

Get your global change biologist vibe on



  • Global Change Biology is a new-ish formal field of biology


  • Focused on understanding environmental change and its effects on (and interactions with) life on Earth


  • Represents a pressing need from early career young biologists and recent graduates of any field


  • Communicated many times a day in the news
    • science and non-science communication
    • ‘code-switching’ will be key

Humans are an unprecendented force on natural systems

  • This is largely a numbers and size game
    • 7.9 billion individuals and growing
    • we are not small organisms


  • Environmental change, largely driven by human forcings, impacts most systems across time & space
    • impacts microbes to mammals
    • impacts marine to mountain ecosystems


  • GCB scientists must:
    • understand past environmental change (for context)
    • evaluate current pressures from humans (for degree)
    • predict trends into the future (for decision making)


  • Today: How does GCB biology work?

The makings of the field of Global Change Biology

  • “On the Influence of Carbonic Acid in the Air upon the Temperature of the Ground.” published by Arrhenius in 1895 while studying ice ages
    • argued that variations in trace atmosphere components (CO2) could greatly influence the heat budget of the Earth
    • Later, he published equations and argued that burning fossil fuels could impact surface temperature


  • Alexander von Humboldt noted that areas surrounding land transformed by agriculture had altered climate (late 1800’s)


  • Guy Callendar published first data linking CO2 and surfaces temperatures in 1938


  • Soon after, studies of the biological impacts of environmental change exploded

What does the field of GCB look like now?



  • Scientific publications are the building blocks of science


  • GCB studies are a key component of the permanent wall of science
    • Now dedicated journals to the field
    • Several high impact journals (Global Change Biology, Nature Climate Change)
    • dedicated books and textbooks


  • Note: communicating science outside of formal publishing is essential
    • indigenous ecological knowledge

GCB scientists face/d an uphill battle

GCB science is interdisciplinary by necessity


GCB embraces diverse perspectives by necessity

Scientific bias an have vast socio-economic consequences

Targets, investment, policy and consequences do not align

GCB is diverse but utilizes same scientific principles


  • Vast array of methods due to diversity of fields
    • ecology, evolution, conservation, physiology, etc.


  • Data generated is super diverse
    • observational study → genomics → climate modeling


  • Stressors to be studied are many


  • Time frames needed are not the same
  • All these studies utilize the same design principles
    • Independent and dependent variables
    • Treatments and controls
    • Main effects and interactions


  • Studies must have replication
    • modeling or genomics may be exceptions


  • Studies should have randomization

Review and critical thinking of experimental design



Simply define independent and dependent variables


Why is a control treatment absolutely necessary?


Why does replication matter for statistics?


If there is an interaction effect between 2 variables (say warming and drought) are you allowed to talk about a main effect by itself (say warming)?

GCB science varies in approach

  • Observe and record natural systems undergoing change without manipulation
    • tuskless elephants, length of butterfly tongues, etc.


  • Search for mechanisms by manipulation (treatments)
    • field or laboratory
    • focus on key variables


  • Use math and computers to predict
    • use measured trends to project forward with some level of uncertainity
    • species interactions to global climate


  • Combine many single studies to understand if broad patterns exist
    • may ignore unexpected or negative results


  • Use citizen participation to increase scope

GCB science uses the entire cool science toolkit

  • Environmental monitoring must be expansive
    • land → atmosphere → oceans
    • satellites → lasers → submarines


  • Lots of different organisms to monitor

    • microbes → plants → whales → humans


  • Biodiversity and species responses are key

    • soil microbiome → adaptation → allele diversity
    • molecular biology tools are vital


  • Many experiments or approaches generate large datasets
    • climate monitoring to genomics
    • advanced computing is often necessary


How is GCB data often visualized? Let’s practice


  • How could we show a significant relationship between 2 key variables?


  • What is the difference between a linear and exponential function (relationship)?
    • draw weak exponential relationships for atmospheric CO2 and ocean pH through time


  • How could you show the results of an experiment with treatments?


  • Why does both the center and the spread of data matter?
    • draw a comparison of control and warming treatments that are likely biologically different